ML20206L483

SER Accepting Request to Delay Submitting Plant,Unit 1 Class 1 Piping ISI Program for Third Insp Interval Until 010430, to Permit Development of Risk Informed ISI Program for Class 1 Piping

ML20206L483
Person / Time
Site:	North Anna
Issue date:	05/10/1999
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20206L473	List: ML20206L466 ML20206L483
References
NUDOCS 9905140036
Download: ML20206L483 (4)

Text

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. k UNITED STATES g NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30006 0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUESTING DELAY IN SUBMITTING CLASS 1 PIPING ISI PROGRAM i VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNIT 1 DOCKET NO. 50-338

1.0 INTRODUCTION

I Inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1,2, )

and 3 components is performed in accordance with Section XI of the ASME Boiler and Pressure

. Vessel (B&PV) Code and applicable addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(l),

10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used when authorized by the NRC if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with ihe specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.

By its letter dated December 22,1998, Virginia Electric and Power Company (VEPCO), the licensee for North Anna Power Station (NAPS) Unit 1, Indicated that it intends to apply a partial scope (Class 1) risk informed inservice inspection (RI-ISI) program on piping at NAPS Unit 1.

NAPS Unit 1 will be updating to the third inspection interval of the ISI on April 30,1999 (ASME Section XI, Program B). The granting of this request will allow VEPCO a delay in submitting the

- Class 1 piping ISI program (NDE, Categories B-F and B-J) for the third inspection interval until April 30,2001, for NAPS Unit 1. The new interval program is being developed to the requirements of the 1989 Edition of ASME Section XI .

2.0 BACKGROUND

2.1 System /Componentinvolved:

VEPCO is requesting a 2-year. delay in submitting the NAPS Unit 1 Class 1 piping ISI program (NDE, Categories B-F and B-J) for the third inspection interval, from April 30,1999, until April 30,2001.

Enciosure 9905140036 990510 PDR ADOCK 05000338 P pm _

I 2-2.2 Licensee's basis for request:

The licensee proposes to apply the Westinghouse Owner's Group RI-ISI program to the piping for NAPS Unit 1. The RI ISI program has the potential to reduce costs and radiation exposure while maintaining high safety levels at the plant. A partial scope (Class 1) RI ISI program on piping is being initially planned at NAPS Unit 1. However, time constraints will not permit VEPCO to develop an Rl-ISI program for NAPS Unit 1 without a schedule delay for implementing a revised ISI program. As such, the limited time to develop a RI-ISI program places an unnecessary hardship (e.g., unnecessary examination costs and personnel exposure) on the plant without a compensating increase in safety, as it would require development and implementation of a 1989 ASME Code ISI program for compliance.

The licensee states in the December 22,1998, letter that:

1. The 2-year delay would apply only to the Class 1 portion of the piping system being evaluated under the Rl-ISI process and the other portions of the ISI program would be required to be submitted in accordance with Part 50.

2. The NDE examinations on the piping to be included in the risk-informed scope would be

- deferred during these 2 years until the RI ISI program is completed.

3. The Code-required pressure testing, repairs or replacements, and associated augmented inspection programs would continue to be implemented as required.

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4. The examinations required for the new interval by the RI-ISI program would still be completed by the end of the interval, including any ASME Code extensions.

5. An RI-ISI program has the potential to reduce costs and radiation exposure, while maintaining high levels of safety at the plant.

6. Since the time constraints will not permit VEPCO to develop an RI-ISI program for NAPS

' Unit 1 without a schedule delay for implementing a revised ISI program, the limited time to develop an RI-ISI program places an unnecessary hardship without a compensating increase in safety, as it would require development and implementation of a 1989 ASME Code ISI program for compliance.-

2.3

Background:

On August 16,1995, the NRC published a policy statement (60 FR 42622) on the use of probabilistic risk assessment (PRA) methods in nuclear regulatory activities. In the statement, the Commission stated its belief that the. use of the PRA technology in NRC regulatory activities should be increased to the extent supported by the state of the art in PRA methods and data and in a manner that complements the NRC's deterministic approach. A part of the PRA implementation plan involves developing guidance for an acceptable approach for utilizing risk .

Information to support requests for changes in plant ISI programs for piping. In addition to the two topical reports submitted by the nuclear industry describing methodologies for implementing RI-ISI and three ASME Code Cases for attemate examination requirements to ASME Section XI, Division I, for piping welds which are under development, the NRC has encouraged licensees to

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3 submit pilot plant applications demonstrating RI methodologies to be used for piping segment and piping structural element selection in systems scheduled for ISI.

NRC Information Notice (lN) 98-44, " TEN-YEAR INSERVICE INSPECTION (ISI) PROGRAM UPDATE FOR LICENSEES THAT INTEND TO IMPLEMENT RISK-lNFORMED ISI OF PIPING,"

issued on December 10,1998, informs all holders of operating licenses for nuclear power reactors that for those licensees that intend to implement a RI-ISI program for piping and do not have a pilot plant application currently being reviewed by the staff, the staff will consider authorizing a delay of up to 2 years in implementing the next 10-year program for piping in order for the licensee to develop and obtain approval for the RI-ISI program for piping.

The staff has indicated that the licensees shall obtain approval for their RI-ISI program at the next available opportunity using staff approved topical reports, i.e., (1) Electrical Power Research Institute, " Risk-Informed Inservice Inspection Evaluation Procedure,"

EPRI TR-106706, June 1996, and (2) Westinohouse Energy Systems, " Westinghouse Owners Group Application of Risk informed Methods to Piping inservice Inspection Topical Report,"

WCAP-14572, Revision 1, October 1997.

The staff further indicated that the request for delay was required to provide adequate justification along with a clear indication of the inspections that will continue before the implementation of the Rl-ISI program, and the licensees will be required during the delay period to continue augmented inspection programs, such as inspection for intergranular stress-corrosion cracking and erosion-corrosion, inspections required for flaws dispositioned by analysis, system pressure tests, and inspection of components other than piping.

2.4 Evaluation

NAPS Unit 1 has indicated the intention to implement an RI-ISI process for Class 1 piping ,

beginning with their next 10-year interval. In accordance with its policy, as stated in the NRC l Information Notice 98-44 discussed above, the staff will consider authorizing a delay of up to 2 j years in the implementation of the next 10-year ISI program for piping only to allow licensees to j develop and obtain approval for their RI-ISI program at the next available opportunity using staff-approved topical reports such as Regulatory Guides, Standard Review Plans, and lessons leamed from pilot applications. The request made by the licensee to delay the development of a RI ISI program for the Class 1 piping by 2 years is consistent with the staff position outlined in IN 98-44. Further, VEPCO's position that the other portions of the ISI program would be ,

required to be submitted in accordance with Part 50 is also consistent with the staff position j outlined in IN 98-44 3 l

The staff finds the licensee's proposed compensatory measures, such as Code-required j pressure testing, repairs or replacements, and associated augmented inspection programs  ;

during the two year period, when the RI ISI for the Class 1 piping is being developed, are consistent with the staff guidance outlined in IN 98-44. The proposed measures would provide  ;

an acceptable level of safety and quality. Further, the staff finds that a temporary delay in the  !

submission of the ISI program update is acceptable in that the subsequent submission thereof, using risk insights, would likely result in the avoidance of unnecessary radiological exposures of plant personnel associated with the inspection of piping that is later found to be unnecessary from a risk perspective.

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3.0 CONCLUSION

The staff finds the licensee's position on the RI ISI (partini scope) is in compliance, as described in 2.4 above, with the guidance outlined in the IN 98-44.

Pursuant to 10 CFR 50.55a(a)(3)(li), VEPCO is granted a delay in submitting the NAr2S Unit 1 Class 1 piping ISI program (NDE, Categories B-F and B-J) for the third inspection interval until April 30, 2001, to permit development of a RI-ISI program for Class 1 piping since the limited time to develop a RI-ISI program places an unnecessary hardship without a compensating increase in safety, as it would require development and implementation of a 1989 ASME Code ISI program for compliance.

Principal Contributor: N. Kalyanam Date: May 10, 1999 l

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